Starting with version 141 of Google Chrome, users are prompted to grant local network access to Chrome when trying to access a website that requires a Duo prompt.
The access window in Chrome looks like the following:
In this case, the site of "example.com" will say "duosecurity.com".
Duo Desktop requires access to the local network in order to function correctly.
Therefore, if you encounter the access request in Chrome for Duo Security, please click Allow.
Note: You should only have to grant access once.